Effect of melatonin supplementation on cryopreserved sperm quality in mouse.

Antioxidants protect spermatozoa against cell damage during cryopreservation.To investigate whether melatonin supplement in the extender may improve the quality of cryopreserved mouse sperm.Kunming mice sperm frozen in extender R18S3 (18% (w/v) raffinose and 3% (w/v) skim milk) supplemented with melatonin were thawed and evaluated.Mouse spermatozoa were cryopreserved in the freezing extender R18S3 that contained melatonin at 0, 0.125, 0.25 and 0.5 mg/mL melatonin. The extender without melatonin supplement was associated with increased formation of reactive oxygen species (ROS) and decreased sperm motility. Melatonin supplement at 0.125 mg/mL significantly increased the progressive motility of sperm in comparison to other melatonin concentration or control. The percentage of thawed viable sperm with ROS was lower in the melatonin-treated groups than in untreated group. Melatonin supplement also increased antiapoptotic gene Bcl-xl expression in the thawed sperm.Supplement of 0.125 mg/mL melatonin could reduce oxidative damage and apoptosis.